Troubleshooting a Hayward Sand Filter For Pools

by Pool Builders on 06-15-2008 in Articles

My sand filter is running at high pressures

Follow the backwashing instructions in your Owner's Manual. The sand bed may be clogged with mineral deposits that will not backwash away. Some calcium based chlorines and other alternative sanitizers will build up in your sand bed, and will require more frequent backwashing and changing of the sand.

Before you replace all the sand in your filter, try removing approximately 1" of the top layer of the sand, replace with the exact amount of sand you removed. Normal life span of the sand is about 4 - 5 years.

You may have to clean your filter system with a special filter cleaner, please call Blue Haven Pools & Spas for more information.

Check to see if there is a closed or partially closed valve along your return piping, open the valve.

Your pump may be too small to provide sufficient flow for proper backwashing. Your filter will function, but a lower design flow rate will cause your system to backwash improperly. Check the output of the pump to be sure that it equals your filter's design flow rate. Replace the pump if it is too small.

My sand filter is running in short cycles

Improper backwashing could be the reason. Always backwash until the water runs clear in the valve's sight glass, usually about two minutes.

You may have live algae causing the filter to clog. By testing the water balance with a test kit and super chlorinating, you should solve this problem.

There is sand at the bottom of the pool

The sand you are using could be too small, which will go through the filter system, then back into the pool. Remove the sand and replace it with the proper grade of sand - #20 Silica or 45-55mm pool sand.

Your pump may be too big for your filter. During backwashing the pressure can cause the sand to rise high enough to overflow into the standpipe, allowing sand to flow back into the pool. Refer to your Owner's Manual for the correct amount of sand for your filter.

There could be a loose lateral located at the bottom of your filter. Tighten any loose laterals, replace if broken.

Most calcium based chlorine, both powder or tablets, contain from 30 - 35% of what is called inert materials. This is calcium residue or dust, which many pool owners mistake for sand. You can confirm this by following these steps: During vacuuming, use a hand vac and pole. As the vac head approaches, the sand will lay on the bottom, and will allow itself to be picked up. Most calcium residue will scatter away from the vac head as you try to pick it up.

If you have this problem, we recommend that you put extra water in your pool and vacuum to the waste line. If you vacuum to the filter, some of it will be trapped on the sand surface, allowing dust to get back into your pool.

The pool won't stay clear

Your pool chemistry may be out of balance, allowing algae to multiply.

The flow rate through the filter may be low due to clogged or undersized piping. Cleaning the lines or changing to larger pipes will correct this problem.

Your filter operation time may not be long enough to compensate for heavy use or hot weather. Try running your filter for 24 hours to clear the water, then adjust to less running time.

Your pump may be hooked up to the wrong port on the multiport valve. If incorrectly installed, the filter will be flowing in reverse. Be sure the pump is connected to the port marked "pump" on the valve.

You could be backwashing too often. Backwash only when the pressure rises 7 - 10 psi over the starting pressure, or when the return flow back into the pool becomes low.

My filter is noisy

An oversized pump may cause noise in your filter valve due to excessive flow. To test, hold your hand partially in front of any returns at the pool wall. If the noise subsides, this will confirm that the problem is excessive flow. It can be remedied by by installing smaller eyeball fittings in the return(s), changing the pump impeller size in the pump, or change to a 2-inch control valve.

My Vari-Flo valve leaks to waste

The valve seat gasket inside the valve has become worn or loose. How do you replace the gasket? You will need a new gasket, some Krazy Glue, and a sharp 1/8-inch wide flat bladed screwdriver.

NOTE: Mark the top and bottom of the valve with a marking pen. It's very important that you do not change the location of the cover when re-assembling. Remove the cover, usually six screws. Using the screwdriver, scrape out every last part of the gasket and cement, in order to get back to a clean flat surface. Put a fair amount of crazy glue on the flat side of the gasket. Place the gasket, flat side down, back into place - let dry for one hour minimum.

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